The thick scaffold beneath the NR membrane (arrow, top) is missing in neurons lacking βIVΣ1 spectrin (bottom).

Scaffolds that hold up membrane proteins in red blood cells also support the channels needed for neuronal signaling, as shown by Lacas-Gervais et al. on page 983.

Neurons fire when sodium channels clustered at the axonal initial segment (AIS) open. This depolarization is propagated by more channels clustered along axons in the Nodes of Ranvier (NR). The structure of these compartments is now shown to rely on a spectrin, relatives of which are needed for the characteristic concave shape of the red blood cell plasma membrane.

The AIS and NR are rich in two spectrins: βIVΣ1 and βIVΣ6. But loss of the βIVΣ1 isoform was sufficient to disrupt AIS and NR physiology. NRs in the mutants were longer and fatter and lacked the protein-dense...

The Rockefeller University Press
2004
The Rockefeller University Press
2004
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